Centrifugal machines

ABSTRACT

The present invention relates to a centrifugal machine in which at least one inflatable lifter is provided on the inside surface of the drum or basket, means being provided for inflating the or each lifter at predetermined intervals to loosen material previously deposited on the wall of the drum or basket.

United States Patent Hine 1 Sept. 25, 1973 1 CENTRIFUGAL MACHINES [56] References Cited [75] Inventor: Gordon Leslie Hine, Denby Dale, UNITED STA ES ATENTS England 2,967,417 1/1961 Bochan 210/372 X [73] Assignee: Thomas Broadbent & Sons Limited,

Huddersfield, Yorkshire, England PW'WY i" ZahPma Assistant Exammer-F. F. Calvetu Flled! 1971 Att0rneyCharles E. Brown et al. [21] Appl. No.: 204,264

[57] ABSTRACT The resent invention relates to a centrifu a1 machine A u t P P g [30] Fgrelgn pp ca Fwnty Data in which at least one inflatable lifter is provided on the Dec. 1970 Great Britain 57,336/70 inside surface of the drum or basket, means being p vided for inflating the or each lifter at predetermined [g2] intervals to loosen material previously deposited on the wallofthe drum or basket [58] Fleld of Search 210/372, 373, 380

. 18 Claims, 7 Drawing Figures i v I 0 Iv -5 E f 12 12 15 PATENTEU SEPZSIBH SHEET 2 0F 2 FIG. 5.

CEN'IRIFUGAL MACHINES The present invention concerns improvements in or relating to centrifugal machines.

The expression centrifugal machine as used herein is defined to include not only industrial centrifugal mas n s tal laan ash washin of F iDlE known as washer-extractors, i.e. those machines which centrifugally dry a laundry load by rotating the load at a" high speed of rotation giving accelerations typically, in excess of 350 g.

During use in certain industrial processes a cake, sometimes several inches thick, builds up around the inside of a centrifugal basket. Periodically therefore it becomes necessary to remove the cake and this is done by the use of a mechanical knife or plough with which an operative scrapes the cake from the inside of the basket.

Similarly, where a washer-extractor washing machine is used, in particular one which includes a horizontally disposed washer drum, three or four spaced lifters are usually fixed to the internal periphery of the drum, and serve to lift and agitate laundry as the laundry drum rotates during a machine washing or rinsing cycle.

During a subsequent spin drying cycle the drum is accelerated to high speed'to centrifugally dry the laundry in known manner. It-has been found however that, particularly on large diameter machines which are heavily loaded, large articles of laundry such as sheets have tended to become trapped. by other laundry and'to bridge between adjacent lifters so that during the spin cycle the articles have been torn by the centrifugal forces.

The presentinvention seeks to overcome this prob lem.

According to the broadest aspect of the present invention there is provided a. centrifugal machine inwhich at least one inflatable lifter is provided on the inside surface of the drum or basket, means being provided for inflating the or each lifter at predetermined intervals to loosen material deposited on the wall of the drum or basket.

The or each lifter may be profiled to assist removal of the loosened material from the drum or basket and if desired the drum or basket may be slowly rotated to assist removal. For example in one configuration each lifter is helically mounted on the inside of the drum;

Where more than one lifter is used, they may be inflated from a common source of pressurized fluid or alternatively each lifter may be inflated separately.

Preferably a plurality of lifters are provided which are equally spaced around the internal periphery of the drum or basket.

The or each lifter may extend along the full length of the drum or basket or only along part of the length thereof. f i

' The means for inflating and deflating the lifter may include a valve controlled source of pressurised fluid such as compressed air.

If desired, when the invention is applied to a washerextractor the lifter or lifters'may be inflated at the conclusion of the various machine cycles to loosen the laundry from the inside wall of the basket.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

FIG. I is a diagrammatic sectional elevation of a laundry washer-extractor embodying the present invention,

FIG. 2 is a sectional end elevation of the washerextractor illustrated in FIG. 1 in the direction of arrow FIG. 3 is a diagrammatic cross-section of a segment of the drum or basket of a centrifugal machine and illustrates one form of inflatable lifter,

FIG. 4 is a similar view to FIG. 3 and illustrates a different form of lifter,

FIG. 5 is a longitudinal sectional elevation illustrating one form of layout of lifters on the drum or basket,-

FIG. 6 is a view similar to FIG. 5 and illustrates an alternative layout, and

FIG. 7 illustrates a still further form of lifter.

In FIG. 1 there is shown a horizontally disposed laundry washer-extractor having a perforated laundry drum 10 which is carried by a shaft 14. The end of the shaft which engages with the drum 10 is tapered and received in a bore in the end of the drum. The drum is mounted fast to the shaft by a key (not shown). The shaft 14 is rotatably mounted in a pair of bearings 12 disposed either side of an electric drive motor M. The drum 10 has a false end wall 16 on the right of the has ket in FIG. 1 as viewed which together with the basket and the end wall defines a radial passage 18.

Three inflatable lifters, each designated 24, and which when inflated are of generally triangular crosssection as may be seen from FIG. 2, are attached to the walls of the drum 10. The lifters are of a laminated rubber construction having an'inflatable inner tube (not shown). If desired however, the inner tube may be dispensed with.

The shaft 14 includes a rotatable pneumatic connector 20 which enables compressed air to be introduced into the passage 18 through a valve controlled compressed air feed line 22 through a centrally bored hole 15. The compressed air is distributed to the lifters 24 through appropriately placed apertures 17 in the false end wall 16.

During use, the lifters are automatically inflated from the feed line 22 at the commencement of each wash or rinse cycle when they serve as heaters and provide the appropriate washing action. The lifters are deflated during the time which the drum l0 accelerates to speed for the spin drying cycle. Deflation of the lifters at this stage of the machine cycle reduces the depth of the lifter by approximately percent and thus the possibility of sheets or other articles becoming torn by centrifugal forces is considerably reduced.

After the completion of the final high-speed spin cycle the lifters are again inflated to strip the laundry work from the walls of the laundry basket where it has tended to cake".

Instead of being triangular in cross-section when inflated as is illustrated in FIG. 2, the lifters may be of generally saw-toothed configuration having a smooth peak as illustrated in FIG. 3 or alternatively again they may be of substantially cycloidal configuration as illustrated in FIG. 4. Alternatively, the lifter may be in the form of a toroidal ring located at any position along the length of and within the drum. For example, the ring may be located in the centre of the drum. Again, if desired, the lifter may be interrupted along its length.

Irrespective of the cross-section of the lifter, the lifter may extend along all or only part of the length of the drum. Moreover the lifters may be helically disposed on the drum surface as illustrated in FIG. 5 or alternatively they may be inclined relative to the longitudinal axis of the drum as is illustrated in FIG. 6.

By using lifters which are arranged on the drum or basket surface as illustrated in FIGS. 5 and 6 at the conclusion of the spin-dry cycle in the case of a washerextractor or at the conclusion of basket rotation in the case of a centrifuge, the lifters may be inflated to loosen the material from the wall of the drum or basket and thereafter the drum or basket slowly rotated to assist removal of the loosened material from the drum or basket.

An alternative form of inflatable lifter construction is illsutrated in FIG. 7. Here the lifter 30 consists of two arcuate plates 31 and 33 which are spaced apart by a plurality of pegs 35 each of which pegs is slidably received in the cylindrical wall of the drum or basket 10. One side of the the plate 31 is profiled to the inside surface of the drum or basket and the opposite surface of the plate 33 is profiled to the outside surface of the drum. A light spring 32 resiliently biases the whole lifter 30 radially outwardly of the drum. A casing 36 is fixed to the outside of the drum 10 and encloses both the plate 33 and an inflatable laminated rubber tube 34. If desired part of the tube 34 may be adhered by a suitable adhesive to the plate 33.

In operation, the centrifugal machine is brought up to operating speed and centrifuging completed. Thereafter the tube 34 is inflated when it bears against the inside surface of the casing 36 thereby causing the lifter 30 to project into the drum or basket 10 against the pressure of the spring 32. Centrifuged material which has collected on the drum surface is loosened therefore and the removal of the material thus facilitated. More-.

over the plates 31 and 33 need not be arcuate but could be planar, or indeed any other desired shape. If desired the lifter 30 may be inclined or helically-disposed on the drum surface to assist removal. 7

Whilst the lifters have been described as being of a laminated rubber construction, they may be made from any other, elastomeric material which is capable of withstanding hot liquid such as water in the case of a washer-extractor. Examples of suitable materials are certain proofed textiles and plastics materials.

It will be understood that the inflatable lifter of the present invention could be located over metal lifters in a centrifugal machine, or they could be provided in addition to metal lifters.

I claim:

1. A centrifugal machine including a rotatably mounted centrifuge drum, and means operative to ro tate said drum, wherein the improvement comprises at least one inflatable lifter disposed on the inside surface of said drum and means for intermittently inflating each lifter to loosen material previously deposited on the wall of the drum.

2. A machine as set forth in claim 1 wherein each lifter is profiled to assist removal of loosened material from the drum.

3. A machine as set forth in claim 2 wherein each lifter is helically disposed on the inside surface of the drum.

4. A machine as set forth in claim 2 wherein each lifter is inclined relative to the longitudinal axis of the drum and on the inside surface of the drum.

5. A machine as set forth in claim 1 wherein each lifter is of triangular cross-section.

6. A machine as set forth in claim 1 wherein each lifter is of generally sawtooth cross-sectional configuration having a smooth peak.

7. A machine as set forth in claim 1 wherein each lifter is of substantially cycloidal configuration.

8. A machine as set forth in claim 1 wherein each lifter is in the form of a toroidal ring.

9. A machine as set forth in claim 1 wherein each lifter is interrupted along part of its length.

10. A machine as set forth in claim I wherein a plurality of inflaters are provided each of which is selectively inflatable from a respective source of pressurised fluid.

11. A machine as set forth in claim 10 wherein means are provided for deflating each lifter prior to the commencement of a spin-dry cycle, when the machine is used as a washer-extractor.

12. A machine as set forth in claim 10 wherein the source of pressurised fluid is valve-controlled.

13. A machine as set forth in claim I wherein each lifter extends along only part of the length of the machine drum.

14. A machine as set forth in claim 1 wherein an inflatable inner tube is provided within each lifter.

15. A machine as set forth in claim 1 wherein at least one metal lifter is provided in addition to each inflatable lifter.

16. A machine as set forth in claim 1 wherein each lifter is of an elastomeric material.

17. A machine as set forth in claim 1 wherein each lifter comprises a pair of plates spaced apart by means slidably received in the machine drum or basket, means biasing the lifter radially outwardly of the drum or basket and inflatable biasing means adapted, upon inflation, to bias the lifter radially inwardly of the drum or basket.

18. A machine as set forth in claim 17 wherein each plate is arcuate and profiled to the cylindrical wall of the drum.

3,760,950 September 25, 1973 Patent No. Dated Inventoflx) Gordon Leslie Hine It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, lines 44- through 53, cancel in their entirety and insert in lieu thereof the following:

17. A centrifugal machine including, a rotatably mounted centrifuge drum, and means operative to rotate said drum, wherein the improvement comprises at least one lifter disposed on the inside surface of said drum, meansfor intermittently projecting each lifter to loosen material i previously deposited on the wall of the drum, each lifter l comprising a pair of plates-spaced apart by means slidably received in the drum, means biasing the lifter radially outwardly of the drum, and said means for projecting each lifter including inflatable biasing means operable upon inflation for biasing the lifter radially inwardly of the drum.

l8. Amachine as set forth in claim 17 wherein each plate is arcuate and profiled to the cylindrical wall of. the

drum.

Signed and sealed this 5th day of February 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER" Attesting Officer Acting Commissioner of Patents FORM po'mso (1069) I USCOMM-DC soars-P69 U.5. GOVERNMENT PRINTING OFFICE i939 0-365-33, 

1. A centrifugal machine including a rotatably mounted centrifuge drum, and means operative to rotate said drum, wherein the improvement comprises at least one inflatable lifter disposed on the inside surface of said drum and means for intermittently inflating each lifter to loosen material previously deposited on the wall of the drum.
 2. A machine as set forth in claim 1 wherein each lifter is profiled to assist removal of loosened material from the drum.
 3. A machine as set forth in claim 2 wherein each lifter is helically disposed on the inside surface of the drum.
 4. A machine as set forth in claim 2 wherein each lifter is inclined relative to the longitudinal axis of the drum and on the inside surface of the drum.
 5. A machine as set forth in claim 1 wherein each lifter is of triangular cross-section.
 6. A machine as set forth in claim 1 wherein each lifter is of generally sawtooth cross-sectional configuration having a smooth peak.
 7. A machine as set forth in claim 1 wherein each lifter is of substantially cycloidal configuration.
 8. A machine as set forth in claim 1 wherein each lifter is in the form of a toroidal ring.
 9. A machine as set forth in claim 1 wherein each lifter is interrupted along part of its length.
 10. A machine as set forth in claim 1 wherein a plurality of inflaters are provided each of which is selectively inflatable from a respective source of pressurised fluid.
 11. A machine as set forth in claim 10 wherein means are provided for deflating each lifter prior to the commencement of a spin-dry cycle, when the machine is used as a washer-extractor.
 12. A machine as set forth in claim 10 wherein the source of pressurised fluid is valve-controlled.
 13. A machine as set forth in claim 1 wherein each lifter extends along only part of the length of the machine drum.
 14. A machine as set forth in claim 1 wherein an inflatable inner tube is provided within each lifter.
 15. A machine as set forth in claim 1 wherein at least one metal lifter is provided in addition to each inflatable lifter.
 16. A machine as set forth in claim 1 wherein each lifter iS of an elastomeric material.
 17. A machine as set forth in claim 1 wherein each lifter comprises a pair of plates spaced apart by means slidably received in the machine drum or basket, means biasing the lifter radially outwardly of the drum or basket and inflatable biasing means adapted, upon inflation, to bias the lifter radially inwardly of the drum or basket.
 18. A machine as set forth in claim 17 wherein each plate is arcuate and profiled to the cylindrical wall of the drum. 